$(document).ready(function(){
    $('.search input[name="search"]').focus(function(){
        if(this.value == 'Search this site')
        {
            this.value = '';
            $(this).removeClass('inactive');
        }
    });

    $('.search input[name="search"]').blur(function(){
        if(this.value == '') {
            this.value = 'Search this site';
            $(this).addClass('inactive');
        }
    });
});